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Don't apply the CPU affinity hack to nix-shell (and other Perl programs)

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As discovered by Todd Veldhuizen, the shell started by nix-shell has
its affinity set to a single CPU.  This is because nix-shell connects
to the Nix daemon, which causes the affinity hack to be applied.  So
we turn this off for Perl programs.
This commit is contained in:
Eelco Dolstra 2013-09-06 16:36:56 +02:00
parent 4b83830d0c
commit 936f9d45ba
5 changed files with 11 additions and 7 deletions
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1
perl/lib/Nix/Store.xs
View file

@ -20,6 +20,7 @@ void doInit()
if (!store) { if (!store) {
try { try {
settings.processEnvironment(); settings.processEnvironment();
settings.lockCPU = false;
store = openStore(); store = openStore();
} catch (Error & e) { } catch (Error & e) {
croak(e.what()); croak(e.what());

1
src/libstore/globals.cc
View file

@ -54,6 +54,7 @@ Settings::Settings()
gcKeepDerivations = true; gcKeepDerivations = true;
autoOptimiseStore = false; autoOptimiseStore = false;
envKeepDerivations = false; envKeepDerivations = false;
lockCPU = getEnv("NIX_AFFINITY_HACK", "1") == "1";
} }

3
src/libstore/globals.hh
View file

@ -183,6 +183,9 @@ struct Settings {
(to prevent them from being GCed). */ (to prevent them from being GCed). */
bool envKeepDerivations; bool envKeepDerivations;
/* Whether to lock the Nix client and worker to the same CPU. */
bool lockCPU;
private: private:
SettingsMap settings, overrides; SettingsMap settings, overrides;

2
src/libstore/remote-store.cc
View file

@ -73,7 +73,7 @@ void RemoteStore::openConnection(bool reserveSpace)
writeInt(PROTOCOL_VERSION, to); writeInt(PROTOCOL_VERSION, to);
if (GET_PROTOCOL_MINOR(daemonVersion) >= 14) { if (GET_PROTOCOL_MINOR(daemonVersion) >= 14) {
int cpu = lockToCurrentCPU(); int cpu = settings.lockCPU ? lockToCurrentCPU() : -1;
if (cpu != -1) { if (cpu != -1) {
writeInt(1, to); writeInt(1, to);
writeInt(cpu, to); writeInt(cpu, to);

11
src/libutil/affinity.cc
View file

@ -33,13 +33,12 @@ void setAffinityTo(int cpu)
int lockToCurrentCPU() int lockToCurrentCPU()
{ {
#if HAVE_SCHED_SETAFFINITY #if HAVE_SCHED_SETAFFINITY
if (getEnv("NIX_AFFINITY_HACK", "1") == "1") { int cpu = sched_getcpu();
int cpu = sched_getcpu(); if (cpu != -1) setAffinityTo(cpu);
if (cpu != -1) setAffinityTo(cpu); return cpu;
return cpu; #else
}
#endif
return -1; return -1;
#endif
} }